Colyn,

 

Our Yahoo ES group has had a long discussion about this recently.  The idea being to eliminate trim travel that never gets used in the normal flight envelope and CG range.  So if you did have a runway trim, it would be controllable or at least more controllable.  I'm not sure what the failure modes are that would create a runway trim motor, but I would guess most involve a stuck switch.

 

On my ES, I use very little of the down trim, but need most of the up trim.  I have done some rough timing of how long I hold the hat switch to get from cruise to landing configuration (the LEDs aren't accurate enough).  It's no more than about 6 seconds total.  The 1.0" servo takes 16 seconds to travel from stop to stop.  Allowing for different CGs, I still have at least 1/3 of the servo travel that's never going to be used.  I have purchased a .7" travel Ray Allen servo to replace the 1.0" travel servo that's installed.  The idea is to keep all the up trim and take away excess down trim.

 

Ray Allen also sells a travel limiter for the .7" servo that will reduce it to .5".  I'm going to install one of the limiters on my rudder trim .7" servo since I rarely need more than a "tap" worth of rudder trim.

 

Mike Easley

Colorado Springs

 

PS Another note, on my ES with a TruTrak, from cruise I can command a 700 fpm descent and it doesn't ask for a trim adjustment, so the amount of down trim necessary for a descent is negligible.